Reflection enhancement of a biopsy needle

Abstract

Method and apparatus for enhancing the reflection coefficient of a surgical instrument for use in conjunction with an apparatus for pulse-echo ultrasound imaging of an area of the body, by means of a diffraction grating disposed on the surgical instrument.

We claim: 
     
       1. Apparatus for performing surgical procedures upon select, internal body tissues, comprising: (a) a pulse-echo ultrasound imaging system for imaging the area of the body including said tissues, said imaging system including transducer means adapted to be accoustically coupled to the exterior of the body; and   (b) surgical instrument means for insertion into the body for performing said surgical procedures, said surgical instrument means having a surface A comprising a diffraction grating for enhancing the reflection coefficient of the surgical instrument means.   
     
     
       2. An apparatus as in claim 1 wherein said diffraction grating comprising a multiplicity of substantially parallel grooves disposed substantially perpendicular to the length of the instrument means, the distance between the depths of adjacent grooves being defined as follows: ##EQU3## where N is an integer, λo is the center wavelength of the transducer and θ is equal to the angle between the incident beam and a line along the surface A and perpendicular to the grooves. 
     
     
       3. An apparatus as in claim 1 or 2 wherein said surgical instrument means comprises a hollow needle. 
     
     
       4. An apparatus as in claim 3 wherein the grooves on said hollow needle extend around the circumference thereof and form a helical pattern. 
     
     
       5. An apparatus as in claim 3 where the tip of the needle has a diameter of 0.1 inches and the depth of the grooves is 0.005 inches. 
     
     
       6. A surgical instrument for insertion into the body and used in conjunction with a pulse-echo ultrasound imaging system for performing surgical procedures, said imaging system including a transducer adapted to direct an incident beam of a given wavelength into the body, and said surgical instrument comprising: a leading edge having a surface including a diffraction grating for enhancing the reflection coefficient of the leading edge of the surgical instrument.   
     
     
       7. A surgical instrument as in claim 6 wherein said diffraction grating comprising a multiplicity of substantially parallel grooves disposed substantially perpendicular to the length of the instrument means, the distance between the depths of adjacent grooves being defined as follows: ##EQU4## where N is an integer, λo is the center wavelength of the transducer and θ is equal to the angle between the incident beam and a line along the surface A and perpendicular to the grooves. 
     
     
       8. A surgical instrument as in claim 7 wherein said surgical instrument comprises a hollow needle. 
     
     
       9. A surgical instrument as in claim 8 wherein the grooves on said hollow needle extend around the circumference thereof and form a helical pattern. 
     
     
       10. A surgical instrument as in claim 8 where the tip of the needle has a diameter of 0.1 inches and the depth of the grooves is 0.005 inches. 
     
     
       11. In a surgical procedure, a method of monitoring an object within the body, said object including a diffraction grating, and the method comprising the steps of: (a) irradiating a body area utilizing pulse-echo ultrasound techniques;   (b) inserting said object into said body area; and   (c) producing an image of said body area, including the enhanced reflection of the diffraction grating of the object.   
     
     
       12. In a surgical procedure, a method of monitoring an object within the body, said object including a diffraction grating on a surface A of said object to enhance the reflection coefficient thereof, said diffraction grating comprising a multiplicity of substantially parallel grooves, the distance between the depth of adjacent grooves being defined as follows: ##EQU5## where N is an integer, θ is equal to the angle between an incident ultrasound beam of center wavelength λo and a line along surface A and perpendicular to said grooves; the method comprising the steps of: (a) irradiating a body area utilizing pulse-echo ultrasound techniques with an ultrasound beam of center wavelength λo;   (b) inserting said object into said body area; and   (c) producing an image of said body area, including the enhanced reflection of the diffraction grating of the object.   
     
     
       13. The surgical procedure of claim 11, wherein said object comprises a surgical instrument. 
     
     
       14. The surgical procedure of claim 12, wherein said object comprises a surgical instrument.